Image pickup lens, image pickup apparatus and mobile terminal
Abstract
The present invention provides an image pickup lens for forming an image of an object on a photoelectrical converter of a solid-state image pickup element. The image pickup lens includes: an aperture stop; a first lens having a positive refractive power and having a meniscus shape whose surface facing the object side is convex; a second lens having a negative refractive power whose surface facing an image side of the image pickup lens is concave; and a third lens having a positive refractive power and having a meniscus shape whose surface facing the object side is convex. Each of the first lens, the second lens, and the third lens includes an aspheric optical surface. The image pickup lens satisfies predetermined conditions according to a focal length of the first lens, and a refractive power of an air lens formed from surfaces of the second lens and the third lens.
Claims
exact text as granted — not AI-modified1. An image pickup lens for forming an image of an object on a photoelectrical converter of a solid-state image pickup element, the image pickup lens comprising, in order from an object side thereof:
an aperture stop;
a first lens having a positive refractive power and having a meniscus shape whose surface facing the object side is convex;
a second lens having a negative refractive power whose surface facing an image side of the image pickup lens is concave; and
a third lens having a positive refractive power and having a meniscus shape whose surface facing the object side is convex,
wherein each of the first lens, the second lens, and the third lens comprises an aspheric optical surface, and
the image pickup lens satisfies following expressions:
0 <P air/ P < 1.0
0.7 <f 1/ f< 1.25
where f is a focal length of the total system of the image pickup lens,
f 1 is a focal length of the first lens,
P is a refractive power of a total system of the image pickup lens, and
Pair is a refractive power of an air lens which is formed from the surface of the second lens facing the image side and the surface of the third lens facing the object side, and which is defined by a following expression:
Pair
=
1
-
n
2
R
4
+
n
3
-
1
R
5
-
D
23
·
(
1
-
n
2
)
·
(
n
3
-
1
)
R
4
·
R
5
,
where n 2 is a refractive index of the second lens for d line,
n 3 is a refractive index of the third lens for d line,
R 4 is a curvature radius of the surface of the second lens facing the image side,
R 5 is a curvature radius of the surface of the third lens facing the object side, and
D 23 is a length of an air space between the second lens and the third lens along an optical axis of the image pickup lens.
2. The image pickup lens of claim 1 , satisfying a following expression:
0<( R 3+ R 4)/( R 3− R 4)<3.0
where R 3 is a curvature radius of a surface of the second lens facing the object side, and
R 4 is a curvature radius of the surface of the second lens facing the image side.
3. The image pickup lens of claim 1 , satisfying a following expression:
1.3< f 3/ f< 4.0
where f 3 is a focal length of the third lens and
f is a focal length of the total system of the image pickup lens.
4. The image pickup lens of claim 1 , satisfying a following expression:
20< v 1− v 2<65
where v1 is an Abbe number of the first lens, and
v2 is an Abbe number of the second lens.
5. The image pickup lens of claim 1 ,
wherein each of the first lens, the second lens, and the third lens comprises a glass material.
6. An image pickup apparatus comprising:
a solid-state image pickup element;
the image pickup lens of claim 1 ; and
a casing comprising a light-shielding material, comprising an opening for an incident light flux from an object side of the image pickup lens, and housing the image pickup lens therein,
wherein the solid-state image pickup element, the image pickup lens, and the casing are formed in one body, and
the image pickup apparatus has a height of 10 mm or less in a direction of an optical axis of the image pickup lens.
7. A mobile terminal comprising the image pickup apparatus of claim 6 .Cited by (0)
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